A technique disclosed herein relates to optical elements including surfaces having antireflection structures configured to reduce reflection of incident light.
In recent years, various optical elements including surfaces having antireflection structures for reducing reflection of light have been proposed.
A technique has been proposed in which fine structural units (e.g., fine structures made of linear recessed portions or linear raised portions, or fine structures made of conical or columnar recessed portions or raised portions) as antireflection structures are formed on a surface of an optical member with a pitch smaller than or equal to the wavelength of incident light.
For example, an optical element disclosed in Japanese Patent Publication No. 2006-053220 includes an antireflection structure provided on a real or virtual curved surface. The antireflection structure includes fine structural units arranged with a pitch smaller than or equal to the wavelength of light whose reflection is to be prevented.